Power train interrupter for changespeed transmissions



June 19,1945." f B KER 2,378,385

POWER TRAIN INTERRUPTER FOR CHANGE-SPEED'I'BANSMISSIQNS Fi-led Jan. 5 1942 five/2X22"; I

@5702" jazz/Z9)" Patented June-19, 1945 PowEa TRAIN m'rERRUP'rEa FOR (.BANGE- SPEED Transmissions Oscar Banker, Evanston, 111., assignor to New Products Corporation, Chicago, 111., a corporation of Delaware Application JanuaryS, 1942, Serial No. 425,625

7 Claims. (01. 192-.01)

This invention has to do with power transmission apparatus for use between an engine and its load and relates more particularly to means for disrupting a power train of such apparatus while driving force is being transmitted thereby.

The present invention is especially useful in motor vehicle installations employing a high ratio power train for operation at cruising speeds but shiftable into a lower ratio train for enabling the engine to more quickly accelerate the vehicle as ing force exerting means, according to the J st recited object, together with means for disabling the same upon the toothed members becoming demeshed.

' A further object is the provision of apparatus, for expediting the demeshing of toothed members in the disruption of their associated power train, that is under supervision of a manipulate when overtaking'and passing another vehicle upon the highway. Since the change from the higher to the lower ratio train is normally executed under conditions requiring a quick shift,

' the practice obtains of providing toothed members in the higher ratio train and which are demeshable under load to disrupt said train and permit the lower ratio train (mobilized during operation of the higher ratio train) to come into operation substantially instantaneously. To insurethat the pressure between the teeth of the meshed members will not be suflicient to' prevent their disengagement, an ignition interrupter circuit has been placed under control of the accelerator pedal to momentarily disable theigni- 'tion when the pedal is pressed slightly beyond open-throttle position. While the engine is thus caused to miss a few power strokes the toothed members are disengaged and thereupon the ignition is restored whereby the engine delivers its power through the lower ratio train.

One objection .to th practice of interrupting the ignition circuit for the purpose and under the conditions just referred to is the consequent pumping of unexploded gas mixture into the exhaust line and the imminent likelihood of its explosion therein. There is the further objection that the ignition circuit may fail to restore, and,

moreover, it is encumbered with auxiliary accessory equipment constituting a, potential trouble source.

An important object of the present invention I is the provision of a novel and improved mechanism, entirely independent of an ignition system, for relieving the tooth pressure between complemental toothed members in a power train to facilitate demeshing of said members during power transmittal through said train. This isaccomplished by applying to one of the toothed members, which is urged by force from the power source to exert tooth pressure upon the complemental toothed member, a suflicient force in opposition to the power source force to-signiflcan'tly diminish the tooth pressure.

An additional object is the provision of opposable power control member for a power source, such as an engine from which the train is driven, and which apparatus is caused by said control member to become eiiective coordinately with predetermined manipulation thereof while in a position causing substantial power output from said source.

Another general object of this invention is the provision of a new brake mechanism operable to momentarily impede the rotation of the drive member of rotating drive and driven meshed toothed members incident to the demeshing of said members in the disruption of a power train which they mobilize when meshed;

The invention further contemplates and has for one of its objects, the provision, in combination with achange-speed transmission wherein there is a synchronizer brake operable to slow the drive part of a Jaw clutch to synchronism with a complemental driven part incident to meshing said parts in eflecting a shift from a lower ratio train into a higher ratio train with which said clutch parts are associated, of means for demeshing said clutch parts while causing application of said brake to reduce the tooth pres-- sure between said clutch parts and thus facilitate demeshing thereof.

. A further object is the provision in a vehicle transmission installation of a demeshing control for applying braking force to the drive member of rotatable drive and driven toothed members demeshable to disrupt a power train, and said de...

- invention, partly diagrammatically, combined with a motor vehicle change-speed transmission and an accelerator pedal or means manipulatable for controlling the power output of the vehicle engine;

Fig. 2 is a back end view of a brake and operating mechanism therefor which is a part of the invention embodiment shown in Fig. 1; and

Fig. 3 is a side elevational view illustrating the governor-actuated cam of Fig. 1 in an actuated position corresponding to fourth speed.

The power transmission apparatus herein illustrated is designed especially for motor vehicle use. Its drive shaft H! is driven from the hub H] of a brake drum H which is preferably driven from the hub E of the runner or driven element of a fluid coupling device (not shown) operated from the vehicle engine in the usual manner.

The drive shaft I9 is connectible through change-speed gearing generally designated T enclosed within .a gear box 2| and for turning a driven shaft 22, the shafts l9 and 22 being journalled in bearings 23 and 24 in the front and back walls of the gear box 2|, and the front end of the driven shaft 22 having a bearing section 25 of reduced diameter piloted within a bearing cavity 2% in the back end of the drive shaft and joiunalled therein upon a set of needle bearings 21 according to standard practice.

Said gearing T has one reverse power train and four forward drive power trains of which the speed ratio is suitable for use in combination with a geared-up differential as that used in as sociation with the rear axle shafts of automotive vehicles., When this transmission is employed in combination with such a geared-up differential the first, second and third speeds which are obtained through power trains including speed reduction gearing respectively correspond to the first, second and third speeds (of which the third is obtained by a direct connection of the drive and driven shafts) of a conventional three-speed transmission with a conventionally geared differtial, whereas the fourth speed or direct drive connection of this transmission corresponds to a fourth or overdrive connection of such a conventional transmission when operating with an overdrive device of well-known character.

The first speed power train comprises a gear 28 integral with the drive shaft I9 and meshed with a countershaft gear 29 which has a sleeve like hub 30 journalled by means of needle bearing sets 3| and 32 upon a countershaft bearing-rod 33 suitably anchored in the ends of the gear box. Power is transmitted from the gear 29 through an overrunning clutch 34 including a drive ring 35, clutch rollers 35 and a normally driven actuator member 31 operative to wedge the rollers against the ring when the latter tends to rotate counter-clockwise (as viewed from the front) relative to said actuator member. This actuator member 31 is integral with a long sleeve shaft 38 which is journalled upon the rod 33 by needle bearing sets 39 and 40. The transfer of power when the teeth of the clutch 4| are meshed. Thus a gear 59 integral with the sleeve it is driven through said clutch and drives a gear 5| which is journalled at its hub 52 upon a hub 53 of an actuator member 54 comprising a part of an overrunning clutch unit '55. This overrunning clutch unit includes clutch rollers 56 and a drive ring 5'! integral with said gear 5| as well as said actuator member 54 which is splined at 58 to the driven shaft 22. The actuator member 54 has cam faces (not shown) so disposed that 'the gear 5| and ring 51 will be effective when rotated clockwise as viewed from the front for causing the rollers to wedge into driving relation between said ring and actuator member so the shaft 22 will be driven from the gear 5|.

The second speed power train includes the drive shaft gear 28, the countershaft gear 29, overrunning clutch 34, sleeve 38, a gear 59 integral with said sleeve 38, a gear til meshed with said gear 59 and journalled upon the driven shaft 22, anda jaw clutch iii of the overrunning type including a driving component of teeth 62 upon the gear 66 and teeth 53 upon a ring t t splined at 65 to the driven shaft 22 and slidable axially of said shaft for meshing and demeshing the said continues through a jaw clutch 4| comprising a driving part of clutch teeth 42 arranged circumferentially about the sleeve 38, a driven part comprising circumferentially arranged teeth 43 upon a sleeve 44 and a clutch ring 45 having internal teeth mutually meshable with the teeth 42 and 43 by sliding said ring forwardly to connect the sleeve 44 for rotation with the sleeve 38. A

groove 46 in the ring 45 facilitates axial sliding of this ring by means of a shifter fork (not shown). When the clutch 4| is disengaged the sleeve 44 is freely rotatable about the sleeve 38 whereon it is carried by needle bearing sets 48 and 49. Said first speed Power train is mobilized teeth. When the clutch El is engaged the second speed power train will be established and during operation of this second speed power train the driven shaft will rotate faster than the gear 5| as permitted by the overrunning clutch 55 while the clutch 4| remains engaged for maintaining the first speed power train mobilized.

Third speed is obtained when the clutch 511 is disengaged and a clutch 66 is engaged. Clutch 65 comprises clutch teeth 51 and 68 which are respectively upon the back end of a ring 59, splined at 10 to the back end of the drive shaft l9, and upon the front face or end of the gear 89. Hence when the clutch 56 is engaged and the clutch 6| disengaged power may be transmitted from the drive shaft to the driven shaft through the third speed power train comprising said clutch 66 gears 60 and 59, clutch 4|, gears 50 and 5| and the overrunning clutch 55 to the driven shaft. Meanwhile the actuator member 31 of the overrunning clutch 34 will be rotated faster than the clutch ring 35 as permitted by the rollers 35.

Fourth speed is obtained by connecting the drive and driven shafts I9 and 22 for rotation in unison and the power train for accomplishing this is established by concurrent engagement of the clutches 6| and 65, power then being transmitted from the drive shaft through said clutch 5'6, the hub of gear 60, clutch 6|, and its splined member 64 to the driven shaft 22. Concurrently the actuator member 31 of overrunning clutch 34 will be driven at an overspeed with respect to the clutch ring 35 as permitted by the clutch rollers 35 and the actuator member 54 of the overrunning clutch 55 will be driven at an parallel with the shaft 22. When the idler gear I81 to rotate counter-clockwise.

1| occupies a forward position, illustrated in Fig. 1, the reverse train is disconnected, but is connectible or establishable when the gear H is slid rearwardly manually, by means of a shifter against the top of the gear box while an opposite end section 9I acts upon the hub of a shifter fork 92 for rotating suchfork and the shaft 88 clockwise, the arrangement being as that illustrated more fully in my copending application the first speed connection by depressing the toe portion of an accelerator 1 (means manipulatable for controlling the engine power output) for accelerating the vehicle engine in the customary manner. The engine throttle (not shown) is operatively connected with the accelerator pedal II1 by a linkage including a link II8, a leg II9 ,of a lever I28, a shaft I2I pivotally mounted in 4 a bracket I22 and fixed to the lever I28 for pivotal movement therewith, an arm I22a fixed to the shaft I2I, and a, link I22b connected with the arm I22a by a lost-motion arrangement consisting of a pin I220 on the link I22b and an Serial No. 357,388. The legs of this shifter fork carry pins 93 projecting into diametrically oppo-.

site portions of a groove 98 in the clutch ring 64 whereby the clockwise movement of said shifter fork will slide the ring 64 forwardly for engaging the clutch 6|. One section of the shaft 88 has an arm 86 rotatively fixed thereon (see lower left-hand portion of Fig. 1) as part of 'control apparatus, later described, for rotating said shaft and said shifter fork counter-clockwise to demesh the clutch 6I at will.

Another cross shaft, I81, carries a shifter fork I88, and a control arm I86, lower right-hand part of Fig. 1, for-said shaft and said fork. Said shifter fork I88 is acted upon by a spring I89, shown in broken lines in Fig. l, coiled about the shaft I81, one end II8 'of the spring reacting against the upper wall of the gear box while the opposite end III is hooked about and acts upon said shifter fork to urge the same and the shaft The legs of the shifter fork I88 carry pins II2 which project into a groove II3 of the clutch ring 69. Therefore, upon release of a stud I85 upon thelower and free end of the arm I88 the spring I89 would be effective for rotating the shaft I81 and the shifter fork I88 counter-clockwise to shift the clutch ring 69 rearwardly for engaging the clutch 66, or placing the ends of the teeth 61 and 68 elongated hole I22d in the arm I22a. Means as the contraction spring I22e fixed at its lower end and connected with the link l22b .at the opposite end tends to hold this link in the endwise position for closing the throttle. When the toe portion of the pedal I I1 is depressed for opening the throttle and causing the engine to accelerate above idling speed the impeller of the aforesaid fluid coupling (not shown) will be caused to rotate sufilciently fast to transmit effective driving force to the coupling driven part E in the usual manner, this driving force being transmitted through the splined connections I5 and 28, the transmission drive shaft I9, gears 28 and 29, overrunning clutch 34, the gears 68 and of this clutch in ratcheting relation should the member 69 be rotating clockwise (as viewed from the front) at a speed in excess of the gear 68 as will be explained presently. However, when the vehicle is at rest as now assumed, a cam plate II I fixed upon a sleeve II5 journalled upon a shaft 19 presents a portion of its long radius profile section H6 in registry with the stud I85- to preclude release of said stud at this time.

Preparatory to starting the vehicle forwardly, any kind of manual control, as illustrated in said copending application Serial No. 357,388, is manipulated for shifting the clutch ring forwardly to engage the clutch 4| and for releasing the cross shaft 88 to place the clutch 6I under control of the spring 89 and a solenoid I82. Under normal starting conditions this solenoid, having a casing I84 with a fiange I85 secured to the gear box 2|, is energized by a circuit starting with ground G in the upper left-hand part of Fig. 1 and leading through contacts (not shown) closed when the engine ignition switch I56 is closed, conductor I55, battery I52, conductor I8I, a switch S closed at this time, a con- 5I, and the overrunning clutch to the driven shaft 22.

As the vehicle proceeds while driven through the first speed train, a speed will eventually be reached at which the transmission drive shaft l9 and the brake drum I1 connected therewith will rotate sufiiciently fast for causing a plurality of centrifugal weights W, of which one is shown in Fig. 1, to pivot counter-clockwise about their pivotal mountings I23 against the urge of a spring'SP, lower right-hand part of Fig, 1, anchored at one end to the gear box by a pin P. Such pivotal movement of the weights W causes their heel portions I24 to shift a ball-bearing thrust unit I 25 (that is, diametrically opposite pins PI in the bearing. sleeve SL of said unit) backwardly against the upper notched ends of the legs of a fork I26 carried non-rotatively upon ductor I8Ia, said solenoid, and a conductor I83 back to ground. Upon this energization of the solenoid. I82 an armature therein holds a connecting link I86 to the right of the'shown position, retaining the arm 86, cross shaft 88 and the shifter fork 92 in their counter-clockwise position against the urge of the spring 89 to hold the clutch 6I' demeshed. r

The vehicle may now be started forwardly in I28. This shaft I21 operates a linkage including an arm A fixed to saidshaft, a link L', and an arm B fixed to the sleeve I I5 rotatable coaxially about the shaft 19 so that upon the aforesaid operation of the speed responsive device in pivoting the weights W counter-clockwise the cam plate Ill will be pivoted clockwise for removing its long radius profile section I I6 from registry with the stud I while positioning a short radius section I29 opposite said stud and thereby placing the shaft I81 and the shifter fork I88 under control of the spring I89 so that this spring is h n eflective for shifting the clutch ring 69 backwardly to place the teeth of the clutch 66 in ratcheting relation since the drive shaft I9 and the clutch ring 69 non-rotatively attached thereto rotate faster than the gear 68 during operation of the first or second speed power trains. The ends of the clutch teeth 61 and 68 are bevelled in the marmer shown to facilitate such ratcheting.

Said cam plate I I4 also has a long radius profile section LR which, incident to said clockwise rotation of said plate, is moved from registry with the operating stem ST of the switch S and a short radius profile section SR which is thus moved into registry .with said stem to permit endwise outward movement thereof for opening said switch, thereby deenergizing the solenoid I 82 and permitting the parts of the clutch 6| to come into ratcheting relation under the force of the spring C89. The rises R and R' between the profile sections LR and SR and sections I I6 and I29 are so disposed circumferentially of the cam that the switch S opens after the arm I06 is pivoted clockwise. While this operating sequence of the rises R and R enables the operator to shift directly into third from first without the contingency of connecting the second speed train, while the vehicle is driven in first at a speed at which portions of the cam sections I29 and LR are in registry with the stud I05 and the switch stem ST, the paramount advantage obtains in the fact that with such arrangement of the rises R and R the rise R will operate first on an automatic shift down from fourth speed to cause disconnection of the clutch GI and establishment of the third speed train.

So long as the accelerator pedal III remains depressed at its toe portion the vehicle will proceed forwardly while driven in the first speed train and the clutch teeth 6i and 62 will continue ratcheting over the teeth 66 and 63. When the operator desires to shift from the first speed train into the second speed train he will simply release the m portion of the pedal I I? which will then return to the position shown, under the influence of conventional spring means as a spring I36, and in doing so will pivot the arm I22a for enabling the spring throttle. Thereupon the engine will decelerate as will the drive shaft I9 and the gear 60, connected therewith through the gears 29, 29 and 59 and the overrunning clutch 34, while the driven part of the clutch 6I continues rotation at substantially constant speed due to the vehicle inertia. During this deceleration of the engine, the gears 50 and 5i will correspondingly decelerate while the normally driven member 54 of the overrunning clutch 55 overruns the gear 5I as permitted by the clutch rollers 56. When the engine slows down sufficiently for the clutch teeth 62 to synchronize with theclutch teeth 63 the spring 86 will slide the teeth 63 into mesh with the teeth 62% for establishing the second speed power train, the drive then being from the drive shaft I9 through the gears 28 and 29, overrunning clutch 34, gears.

59 and 60 and the clutch 6I to the driven shaft 22. The normally driven member 54 of the overrunning clutch 55 will continue to overrun the normally driving ring 51 of this clutch. g

I22e to close the engine' Normally, the shift up from second is into fourth or direct drive, and when the operator executes this shift he will again simply release the toe portion of the pedal II! for closing the engine throttle. Thereupon the engine will de-- celerate as will the drive shaft I9 and the clutch ring 69, while the driven shaft 22 and the gear connected therewith through the clutch 6I will continue rotation at substantially constant speed clue to the vehicle inertia. During this deceleration of the engine, the gears 28 and 29 will correspondingly decelerate while the gear 59, meshed with the gear 60, and the normally driven member 31 of the overrunning clutch 34 overruns the clutch ring 35 as pc mitted by the clutch rollers 36. When the engine slows down sufficiently for the clutch ring 69 to synchronize with the gear 60 the spring I09 will slide the teeth 61 into mesh with the teeth 68 for establishing the fourth speed power train, the drive then being from the drive shaft I9 through the clutch 66, the hub of the gear 60 and the clutch 6| to the driven shaft 22. The normally driven member 31 of the overrunnin'g clutch 34 will continue to overrun the normally driving ring 35 of this clutch.

I provide under control of the accelerator pedal III means for expediting deceleration of the drive shaft I9 for more quickly synchronizing the parts of the clutches 6i and 66 so that less time is required in shifting from first to second and from second to the fourth in the manner just described. This synchronizer means comprises a synchronizer brake band I3I, Figs. 1 and 2, frictionally'engageable with the circumferential periphery of the brake drum IT for resisting rotation thereof.

Referring now to Fig. 2, the brake band IBI is shown as having upon one end a bracket I32 on which there is an apertured ear I33 wherein there is disposed a bolt I34 which projects through an apertured boss I35 upon the inner side of the clutch casing I28. The ear I33 is normally held firmly against the face of the boss I35 adiacently thereto by means of a helical spring I36 about the bolt I34 and exerting expansive force against the opposite face of the boss I35 and a spring seat It'll held in selected position axially of the bolt by means of a nut I A collar I39 limits-the distance the bolt Iii-l can move endwise in the stud I35 while compressing the spring I36. Upon the opposite end of the brake band I3! there is formed a loop Ilil in which there is disposed a pintle member I lI. A bell crank I42 pivotally mounted upon a pin I43 anchored in the clutch casing I28 is connected with the pintle I4I at one of its legs while the other leg of the bell crank is connected by a link I44 with an end of a reciprocal rod I45 which is connected with a motor diaphragm (not shown) within a motor I46. This motor is energizable by a vacuum line connected with a low pressure source as the intake manifold of the vehicle engine, said line including conduits I4I and I48 respectively connected with the motel-I46 and said low pressure source and through which intercommunication is controlled by a valve 6%. The valve I49 is in turn controlled by the armature of a solenoid I56, the latter being effective when energized by the passage of an electric current therethrough for moving its armature in a manner to cause communication of sa d low pressure source with the motor I46 through the valve Hit and said conduits I47! and I 56. The valve I49 may be of the character shown in detail in my U. S. Patent No. 2,171,534, issued September 5, 1939. When the motor is thus connected with the low pressure source, the said diaphragm therein will be caused to move upwardly whereby the bell crank lever I42 will be rotated counterclockwise with sufiicient force to cause the band I3I to apply substantial frictional drag or braking action upon the drum H which normally rotates in the direction of the arrow.

While the motor I46 is operable when connected with a low pressure source, it will be understood that this motor may be designed to operate in response to liquid or gas pressure applied thereto, or, any other type of motor may be used in place of the motor I46.

The electric circuit for controlling energization of the solenoid I50 starts with ground at G and includes contacts associated with the ignition switch I56 and closed when said switch is closed, a conductor I55, the battery I52, a conductor I53, a switch I54 under the control of the accelerator pedal IN, a conductor I5'I, a normally closed switch I58, conductors I59 and 159a between sai" meshing the clutch 6|.

switch I58 and the solenoid I50, a conductor and a normally closed switch I94 operable when closed to connect the opposite side of the circuit with ground for completing the same. The switch I54 includes contact members 'between which circuit is closed when the bell crank I is rotated counter-clockwise to the position shown (pursuant to release of the accelerator pedal I81) to press an operating stem I6I of the switch downwardly. The switch I58 comprises a casing I64 mounted upon the gear box '2I and insulatively supported terminal members I65 and I66 which are normally mutually engaged by a circuit closing bridge I61 held in the position shown by a spring I68 which is insulated from the casing I64 by an insulator seat I69. A 'pin I10 is connected with the conductor bridge I61 by means of an-insulator member "I. A boss I12 abuts against thelower end of the stem I10 to lift the conductor bridge I61 from engagement with the demeshing the clutch 6|.

contacts I65 and. I66 when the shifter fork I 08 is rotated counter-clockwise for engaging the clutch 6".

It Will be seen therefore that upon release of the accelerator pedal II! for initiating the automatic change from second to fourth speeds, for example, each of the switches. I54, I56, I 58 and 194 is closed so the solenoid I50 will be energized for causing application of the synchronizer brake band I3I upon brake'drum I1 to quickly decrease the speed of the clutch ring 69 to the speed of the gear 60 so the clutch 66 will engage for immediate establishment of the fourth speed train. When this train is established, however, the boss I12 will cause the switch I56 to open the pedal II1 will fail to energize the solenoid I 50 and the synchronizer brake I3I will not be overcome by a spring SP whereby the sleeve SL will move forwardly to allow rotation of the cam plate II4 far enough counter-clockwise (as from the fourth speed position shown in Fig. 3-) to carry the rise R past the stem ST for closing the switch S and thus energizing the solenoid I82 and de- The transmission is thus conditioned for driving through the third speed train should the engine then be accelerated. But should the engine and drive shaft I9 be allowed to slow down predeterminedly further the spring SP will further overcome the inertia force of the weights W whereupon the sleeve SL will move forwardly far enough to permit passage of the rise R under the stud I05 for demeshing the clutch 66 so that if the engine is thereafter accelerated the drive will be through the first speed train. During deceleration of the engine and drive shaft to the speed at which the rise R is carried under the stud I05 it will he noted the clutches 34 and 55 are overrunnin'g whereby the clutch. 66 is relaxed to facilitate demeshing thereof by the cam rise R.

While operating in fourth speed, the operator wherefore subsequent depression and releaseof may shift to third speed instantaneously, at will,

by simply depressing the heel portion of the accelerator pedal II1 whereby a base member I13 upon which said pedal is mounted, together with a stem I14 connected with said base member, is shifted axially downwardly against the force of a spring I15 of which the ends bear oppositely against the member I13 and a bracket I16 suitably connected to the under side of a floor board I11 in the driver's compartmentof the vehicle. Downward movement of the stem I14 causes pivotal movement of a lever I18 for closing a switch I19 whereby an electric circuit is energized for energizing the solenoid I 82 and thus Ordinarily when the heel portion of the accelerator pedal H1 is depressed for causing demeshing of the clutch 6| the toe portion of that pedal will be released wherefore little or no substantial pressure will exist between the teeth upon the counterparts of said clutch. Under these conditions the solenoid I82 can readily demesh the clutch. However, when the present apparatus is used upon a motor vehicle wherein it may be desired to shift 1 downwardly from the fourth speed connection to the third speed connection while the engine is delivering power through the fourth speed conmotion, as when the vehicle is to quickly overtake and pass another vehicle upon the highway, the pressure may be suflicient between the teeth of the clutch 6| to prevent demeshing, unless means is provided for diminishing the tooth pressure.

. In the illustrated form of the invention the circuit energized by the closing of the switch I19 also causes application of the brake band I3I of the synchronizer brake onto the brake drum I1 and in this manner opposing the driving 'force of the engine sufliciently to materially diminish the pressure of the teeth 62 upon the clutch driving counterpart against the teeth 63 upon the driven counterpart.

Electric energy for the aforesaid electric circuit is obtained from the source I52 through the conductor I8I, a lateral conductor 202 connecting with one side of the switch I19, a conductor 203 leading out of the switch I19 and which is adapted to be electrically connected by said switch with the conductor 202 when the switch is closed. The conductor 203 leads to one coil 204 of a double coil relay Re and the opposite end of said coil 204 is connected with ground through a conductor 205, a pair of normally closed relay contacts 206 and 201 and a conductor 206. Said relay R includes a second coil or winding 208, a pair of normally open contacts 2I0 and 2H and a second pair of normally'open contacts 2I2 and H3. The movable contacts 2 and 2I3 are connected with the ungrounded side of the electric energy source I52 through the conductor I53 and a conductor 2I4. Contact 2I0 is connected with one end of the relay winding 209 whereas the opposite end of said winding is connected by conductor 2I5 with a movable contact 2I'6 which is normally engaged with a fixed contact 2I1. The circuit continues from the fixed contact 2I1 through a conductor 2; and the short conductor I59a to the above described solenoid I50 which when energized opens the valve I49 for causing I application of the brake band I3I upon the syn-v chronized brake drum I1. The fixed relay contact 2I2 is connected with the solenoid I82 by a conductor 2I9. 1

Operation of the just described electric circuit is as follows: 7 Y

It will be assumed that the driver of a vehicle upon which the present apparatus is installed is cruising alongthe highway with the fourth speed powertrain of the transmission in o ation and that he overtakes another vehicle whic he wishes to pass. In order to enable him to accelerate quickly for overtaking and passing said vehicle he will press upon the heel portion of the accel tion fOr closing the switch I19.

201 by the boss 220 erator pedal for closing the switch I19, without necessarily releasing the toe portion of this pedal. Electric energy will then flow from the source I52 through the conductors I8I and 202, said switch I19, conductor 203, relay winding 20, conductor 205, contact pair 206201 and the con- 2| I and 2 I2-2 i3 close prior to the opening of the 1 contact pair 206-201, an operating characteristic obtained in a manner well-known in the relay art. This assures that a stick circuit including the contact pair 2I02Il will be established before the braking of the energization circuit by the opening of the contact pair 206-401. Said stick circuit is provided from the battery conductor 2 I4, and through the then closed contact pair 2I0-2I i, the other winding 209 of said relay, conductor 2l5, contact'pair 2I6-2I'I, conductors 2I8 and I59a, solenoid I50, conductor I60 and the normally closed switch I94 to ground. The just traced stick circuit in addition to holding the relay Re energized, energizes the solenoid I50 for causing application of the synchronizer brake I3I-II, effecting a snubbing action upon the transmission drive shaft I9 and hence upon the driving counterpart of the jaw clutch GI. During this snubbing action for decreasing the net driving force applied to said clutch driving member, the circuit concurrently closed from the battery conductor 2 through the relay contact pair 2 I2-2 I 3 and the conductor- 2I9 to the solenoid I82, causes energization of said solenoid and the operation of the arm 86, cross shaft 88 and the shifter fork 92 for withdrawing the driven counterpart of the clutch 6| from mesh with said driving counterpart. It will be noted that the hub of said arm 88 is provided with a boss 220 which is operable immediately upon the demeshing of the clutch 6 I to separate the contacts 2IG and 2H by pressing against an extension 22I upon the movable contact 2I6. Such opening of the contacts 2 I8 and 2" brakes the energization circuit for the solenoid I50 whereby the synchronizer brake is released. This circuit, broken by the contacts 2I0 and 2I1, further causes deenergization of the relay winding 209 and hence of the relay Re since this is the only winding energized at this time. Said boss 1 220 when thus rotated with the arm 86 also becomes interposed in the return path of an extension 222 on the movable contact 206 as indicated by the dotted lines in Fig. 1 to prevent closing of the contact pair 206-20! for reenerglzation of the relay until after subsequent clockwise movement of the arm 85 to the normal position shown.

Ordinarily the operatorof the vehicle will but momentarily press the accelerator pedal heel por- However, should the operator inadvertantly hold this pedal portion down, keeping the switch I18 closed until after the third speed power train is established. no injury will be caused to the apparatus, for upon the demeshing of the clutch 6| the contact pair 2I6-2I'| i opened to cause release or the brake band I8I from the brake drum I1, and the contact 206 is maintained separated from its mate its counter-clockwise position for maintaining the clutch BI demeshed. Therefore, potentialization of the conductor 203 cannot cause energization of the relay winding 204 and the relay so long as the arm 86 is in or vehicle,

winding 209 cannot energize for energizing the relay Re so long as the contacts 2I6 and 2H are separated. However, upon subsequent reestablishment of the fourth speed power train, or establishment of the second speed power train incident to which the clutch SI is meshed and the stud 220 is in the position shown in Fig. 1, the contact pairs 206--201 and- 2I6-2II will again assume their normal closed relation, conditioning the apparatus for a subsequent operation at the will of .the operator. I

While an electromagnetic motor comprising the solenoid I82 is shown herein for developing the work energy for opening the jaw clutch BI, it is within the contemplation of this invention that a control solenoid as I together with an associated control valve as I49 and amotor as I 46 could be employed instead of the solenoid I02.

Should the operator, while the vehicle is being driven through the second speed "train, wish to change to the first speed train to obtain more driving power from the engine or to enable him to maneuver the vehicle under closer supervision, he may do so instantaneously by momentarily depressing the heel portion of the accelerator pedal I I! for closing the switch I'I9and energizing the solenoid I82 in the aforedescribed manner to rotate the arm 86, the shaft 88 and the shifter fork 92 counter-clockwise for disengaging the clutch 6 I. Since the clutch, will already be disengaged at this time, both the clutches GI and 66 will then be disengaged so that establishment of the first speed train is immeditaely obtained. Upon the establishment of this power train the gear 59 will drive the gear 60 faster than the gear 50 drives the driven shaft 22 through the overrunning clutch wherefore the clutch teeth $22 will rotate faster than the teeth 63 so these teeth will simply ratchet harmlessly upon deenergization of the solenoid I82 whereby the spring 09 is again effective for sliding the teeth 63 axially against the teeth 02. Therefore, a shift can now be made from the first speed train to the second speed train at will by momentarily releasing the accelerator pedal to permit the engine and the drive shaft I9 to decelerate sufficiently for the gear to synchronize with a driven shaft at which time the sprin 89 will slide the teeth 63 forwardly into mesh with the'teeth 62 to establish the'second speed train. During the synchronization period the switch I54 will be closed as will the switches I56, I58 and I96 so the solenoid I50 will be energized. for causing application of the synchronizer brake band I3I to expedite synchronization of the driving and driven components of the clutch BI in the manner above described with respect to the corresponding componentsyof the clutch 06. However, when the accelerator is later depressed at itstoe portion for taking up the drive through the second speed train it will be noted that the lost-motion connectionconsisting of the pin I220 and the elon-' gated opening I22d will provide for the switch I54 being opened to release the brake band lfil before the engine throttle is opened so the action of this brake band will not first oppose the engine driving force and'then quickly release, resulting in a surge of power from the engine.

It will be seen that I have provided an effec tive means, independent of the engine ignition or other essential operating parts of the engine for diminishing the pressure between the teeth of a clutch during the interval of time while it is being demeshed for disrupting a power train with which said clutch is associated. This means for decreasing th 'clutch tooth pressure .with the demeshing oi. said toothed members to is readily adapted for operation under control of a vehicle accelerator pedal, and has theiurther advantage of making use of a synchronizer brake which comprises a part of the transmission withwhich said means is afilliated.

While I have herein shown and described a preferred embodiment with the view of fully illus- 1. In a power transmission system for use between a load and an engine controllable in power output by the manipulation of a control means therefor, which system includes a power train having toothed members meshable to establish such train in driving relation between said load contravene said actuation of the brake means.

5. In apparatus for drivingly connecting a load with an engine controllable in power output by manipulation of a control means therefor, a change-speed transmission comprising a' Plurality of diilerent speed ratio power trains individually establishable in driving relation between the engine and load, a. higher speed transmitting ratio of said. trains including drive and driven toothed members respectively rotatable with and according to the speed 01' the engineand the load and meshable for establishing such train when eluding means operable coordinately with .predetermined manipulation of said control means, while the latter is in a position causing substantial power output of the engine, to counteract said urge or the engine upon said one toothed member and thus diminish said tooth pressure, means operable to demesh said toothed members, and means operable coordinately with said predetermined manipulation of said control means to operate said demeshing means during the diminution of said tooth pressure.

2. The combination set forth in claim 1, and wherein there is means operable coordinately with the demeshing oi said toothed members to contravene the operation of said counteracting means. a

3. In a power transmission system for use between a load and an engine controllable in power output by the manipulation of a control means therefor, which system includes a power train having toothed members meshable to establish such train in driving relation between said load and engine whereby teeth of one such member incur pressure upon teeth of the other pursuant to the transmission of power by said train from the engine to the load, and which toothed memhere are demeshable to disestablish said power train incident to the establishment of a different driving connection between-said engine and load: means for so disestablishing said power train, comprising brake means including a part operably connected with said one toothed member, means operable coordinately with predetermined said members are synchronized, brake means including a part connected for rotation with the drive toothed member, means operable coordinately with predetermined manipulationv of said control means, in decreasing'the engine output, to cause actuation of said brake means for decelerating the drive toothed member to synchronism with the driven toothed member to facilitate meshing of said members incident to a shift upwardly into said higher ratio train, a lower ratio or said trains including an overrunning clutch to enable such train to remain mobilized while the higher ratio train is established and in operation and preparatory to taking up the drive upon demobilization of the higher ratio train, demeshing mea'ns actuatable to demesh said toothed members, means operable coordinately with a diflerent predetermined manipulation of said control means, while in a position causing substantial engine output, to cause actuation of said brake means and consequent diminution of the pressure between the teeth of said toothed members, and means operable coordinately with such diflerent manipulation of said control means to. actuate said demeshing means during said diminution of tooth pressure.

a 6. In a power transmission system having a power train including rotatable drive and driven toothed members demeshable to disrupt said train; means for disrupting said. train while it is transmitting force, and hence while teeth of the driving member exert pressure upon teeth of the driven member, comprising demeshing means operable to demesh said teeth, brake means operable to resist rotation of said driving member,

and electric circuit means including electrically controlled means operable upon a predetermined condition of said circuit means, with respect to its energization, to cause operation of said demanipulation of said control means, while in a position causing substantial power output of the engine, to cause actuation of said brake means to constrain said brake part to modify the position of said one toothed member relatively to the other for. diminishing said pressure between their teeth, means operable to demesh said toothed member's, and additional means operable coordinately with such predetermined manipulation of said control means to operate said demeshing means during the diminution of said tooth pressure.

4. The combination set 'forth in claim 3, and wherein; there is means operable coordinately rmeshing means, an additional means operable upon said predetermined circuit condition to cause operation of said brake means and consequent diminution of said tooth pressure to facilitate said operation of the demeshing means, switch means operable to create said predetermined circuit condition, and switch means operable coordinately with the demeshing of said' toothed members to alter said predetermined circuit condition for terminating the operation of said brake means.

'7. In a power transmission system having a power train including rotatable drive and driven toothed members demeshable to disrupt said train and for use between a. load and an engine that is controllable in power output by manipulatable control means; means for disrupting said train while it is transmitting iorce,'and hence while teeth'of the driving member exert pressure upon teeth of the driven member, comprising demeshing means operable to demesh said teeth, brake means operable to resist rotation of said drlvingmember, and electric circuit means ineluding electrically controlled means operable upon a predetermined condition of said circuit means; with respect to its energization, to cause operation of said demeshing' means, and additional means operable upon said predetermined circuit condition to cause operation of said brake means and consequent diminution of said tooth pressure to facilitate said operation of the demeshing means, switch means operable coordinately with a predetermined manipulation of said control member while the latter is in a position for causing substantial power output of the en-, 

